1. Technical Field
The disclosure relates to an implant that is placed into a living body, and an implant assembly that includes the implant.
2. Background Art
In the medical field, techniques relating to implants that are placed into living bodies and various techniques relating to methods for placing the implants into the living bodies are known. For example, International Publication No. WO 2009/006258 discloses an implant that is placed between spinous processes of the living body to treat lumbar spinal canal stenosis.
In the related art, an expansively deformable balloon is injected with a filling material and the balloon is used as an implant for spacing between the spinous processes. The balloon injected with the filling material causes the distance between the adjacent spinous processes to be expanded and maintained with a predetermined gap. The balloon functions as a spacer which is placed in the living body over a long period of time. A relatively rigid material is sometimes used as the filling material so as to maintain an expanded state of the balloon over a long period of time. However, when the rigidity of the filling material is high, a load on the spinous processes and living body tissue present around the spinous processes increases, and thus, this type of implant is not suitable to be placed in the living body over a long period of time.
U.S. Patent Publication No. 2010/0249841 discloses an implant for spinous processes that includes an inner side container forming a space to hold the filling material and an outer side container which is arranged in an overlapping manner so as to cover a part of an outer circumferential surface of the inner side container. This implant is capable of addressing the problem of WO 2009/006258 described above by filling the inner side container with the filling material and filling the outer side container with a relatively flexible material. However, in order to allow the inner side container to be filled with the filling material and additionally allow the relatively flexible material to be introduced into the outer side container, a plurality of introduction paths (catheters and the like) must be used to communicate with the respective containers. When the plurality of introduction paths are used, a larger wound hole must be formed in the living body during the introduction of the implant into the living body, which is problematic in that the introduction of the implant cannot be performed in a minimally invasive manner.
Therefore, there is a need for an implant which can be introduced into the living body in a minimally invasive manner and can reduce the load on the living body while in use regardless of the type of the filling material used to maintain the expanded state, and an implant assembly including the implant.